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From: Michael Heerdegen <michael_heerdegen@web.de>
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Subject: Re: delete all whitespace (space) in a region
Date: Tue, 14 Nov 2023 10:33:26 +0100
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Andreas Röhler <andreas.roehler@easy-emacs.de> writes:

> The latter updates the end, whereas the previous keeps the old limit,
> which may do unexpected deletions.

Indeed.  In such cases using markers is useful:

  (unless (markerp end)
    (setq end (copy-marker end)))

If you want to be kind to the gc, invalidate the marker at the end of
the function:

  (move-marker end nil)


Michael.